I used 2 ways to solve the problem and ran them in Python GUI. Both of them can get the right result("Hy lk Wrds!").
However, on the online board, only the 2nd solution(codes after line 13) works. The 1st solution(codes before line 13) will get this error: Oops, try again. Your function fails on anti_vowel("Hey look Words!"). It returns "None" when it should return "Hy lk Wrds!".
Replace this line with your code.